Question

Tadeh launches a model rocket straight up from his backyard that takes 6.96 s to reach its maximum altitude. (After launch, the rocket's motion is only influenced by gravity. Enter magnitudes only.)
(a) What is the rocket's initial velocity?

m/s

(b) What is the maximum altitude reached by the rocket?

m

Answer 1

a)

Use the equation of motion: v = u + at

=> v = 0 m/s, a = -9.8 m/s^2, t = 6.96 sec

=> u = v - at = 0 - (-9.8)(6.96)
= 68.2 m/s

b)

Use the equation of motion: 2as = v^2 - u^2

=> a = -9.8 m/s^2, v = 0, u = 68.2 m/s

=> 2(-9.8)h = -(68.2)^2
=> 2*h = (68.2)(6.96)
=> h = 474/2
= 237 m